In general, an office chair has a basic function for a user to sit at work, and also has a function as a space for waist protection and relaxation.
Most people including students or office workers spend substantial amount of time in their daily life in chairs. Thus, since a load of an upper body is transferred to a spine and pelvis, stress is applied to the spine, the pelvis and muscles around the spine and pelvis, so that people may suffer from a feeling of fatigue or pain.
Further, when people do not maintain a correct sitting posture due to an incorrect sitting posture or a badly designed chair, a spinal disk disorder (herniated lumbar disc) may be caused.
For this reason, a corrective chair capable of correcting the sitting posture to prevent the spinal disk disorder has been suggested, and the corrective chair that is often exposed in daily life is ergonomically designed. However, most corrective chairs according to the related art do not customize to the user, and the user may need to adjust the corrective chair when the user sits in the chair.